This invention relates to the use of polyvinyl alcohol fatty acid esters, notably unsaturated fatty acid esters, as fat replacements in food and pharmaceuticals. Polyvinyl oleate is a preferred compound in this new class of edible fat replacements.
Since fats provide nine calories per gram compared to four calories per gram provided by protein or carbohydrates, major research efforts toward reduction of caloric intake for medical or health reasons have focused on ways to produce food substances that provide the same functional and organoleptic properties as fats, but not the calories. Analogues of natural triglyceride fat, sugar fatty acid polyesters and similar derivatives of other polyhydric compounds, neopentyl alcohol esters, esters of di- and tri-carboxylic acids, jojoba oil, silicone oils and various polysaccharides have been suggested for use as edible fat replacements. (For recent reviews, see Hamm, D.J., 49 Food Sci. 419 (1984), and Haumann, B.F., 63 J. Amer. Oil Chem. Soc. 278 (1986).)
In the selection, modification, and/or synthesis of low calorie replacements of edible fats and oils, the polymeric fat replacements, for example, polysaccharides, have a great deal of structural flexibility because of the inherent nature of polymers. Not only may side chain fatty substituents attached to a chemical structure be varied to achieve different chemical and physical properties (as was the case, for example, with the hydrogenated, partially hydrogenated and unhydrogenated fatty acids condensed with sucrose in Eur. Pat. Ap. No. 235,836 to Bodor and Page and in Eur. Pat. Ap. No. 236,288 to Bernhardt to make different sucrose polyesters), but the entire structure may be shortened or lengthened to make macromolecules of enormously differing functionality.
A number of branched and linear polysaccharides and lower molecular weight dextrins and amyloses have been suggested as fat replacements in foods. Polydextrose, a tasteless non-sweet low calorie bulking agent formed by the random polymerization of glucose with lesser amounts of sorbitol and citric acid, has been used as a partial replacement for fat (and sugar) in a variety of common processed foods, including desserts (U.S. Pat. No. 4,626,441), dairy products (U.S. Pat. No. 4,631,196), and crackers (U.S. Pat. No. 4,678,672). Polyglucoses and polymaltoses, prepared by the polycondensation of saccharides in the presence of a polycarboxylic acid catalyst, were synthesized and used in dietetic foods in U.S. Pat. No. 3,876,794 to Rennhard and combined with dietary fiber in U.S. Pat. No. 4,304,768 to Staub et al.
Converted starches (mostly from tapioca, corn, and potato starches), prepared by the chemical, thermal, or enzymatic degradation of starch molecules to lower molecular weight fragments (including dextrins and amyloses), were disclosed as fat- or oil-replacements in foodstuffs in U.S. Pat. Nos. 3,962,465 and 3,986,890 to Richter et al., U.S. Patent No. 4,247,568 to Carrington and Haleck, and U.S. Pat. No. 4,510,166 to Lenchin et al. Modified high amylose starches have been employed as fat extenders in imitation cheeses (U.S. Pat. No. 4,504,509, U.S. Pat. No. 4,608,265, and U.S. Pat. No. 4,695,475) and in batter coatings for baked food products that resemble fried foods (U.S. Pat. No. 4,504,509). An anionic polysaccharide obtained from algae was disclosed with mono and/or disaccharides to extend fats in whippable emulsions in U.S. Pat. No. 3,944,680 to van Pelt et al.
Polyglycerol esters comprise another class of polymeric fat replacements. Widely used as emulsifiers, polyglycerol fatty esters are wax-like solids which may be used with hydrophilic colloids to form compositions oleaginous in appearance and texture, but containing substantially no fat. Linear and cyclic polyglycerols of different chain lengths have been prepared for consumption in food (U.S. Pat. No. 3,968,169), and substituted with a range of fatty acid residues (U.S. Pat. No. 3,637,774) for use in margarine, imitation butter, cheese spreads, dips, puddings, icings, salad dressings, sauces, and frozen desserts, including ice cream and sherbet (U.S. Pat. Nos. 3,637,774 and 4,046,874).
Though great variations in chain length and structure are possible with the currently available polymeric fat substitutes, most have the disadvantage of being at least partially, if not totally, digestible. (See Haumann, supra, pp. 278-280, for a discussion of polysaccharides, and Babayan, V.K., 41 J. Amer. Oil Chem. Soc. 434 (1963), for polyglycerol esters.) In addition, polymerization reactions are hard to control. The direct free radical polymerization of vinyl esters of unsaturated fatty acids, for example, do not form linear polymers, but polycondense to form cross-linked products (Seymour, R.B., and Carraher, C.E., Polymer Chemistry, Marcel Dekker, New York, 1988, chapter 9).
By the same token, degradation reactions are hard to control. Thus, close attention must be made to the conditions under which starches are degraded to form dextrins and sugars (U.S. Pat. No. 4,510,166). Homogeneous products are difficult to achieve, and vary greatly with the starting material used. Even if the starting material were a pure compound, which most natural products are not, the sugar moieties making up polysaccharide chains have myriad functional groups that can react, and geometric and optical isomerism further complicates condensation reactions. (In the esterification of a single sucrose molecule with an excess of fatty acid, for instance, the eight hydroxyl groups can react to form 255 different sucrose esters if all isomers are counted; see Weiss, T.J. et al., 48 J. Amer. Oil Chem Soc. 145 (1971).)